1. I. P. Lapin, Zh. Vses. Khim. Ova. im. D. I. Mendeleeva,21, No. 2, 151 (1976).
2. N. G. Lopatina, Communicative Activity in the Honeybee (Apis mellifera) Family [in Russian], Nauka, Leningrad (1971).
3. V. V. Ponomarenko, N. G. Lopatina, V. G. Marshin, I. A. Nikitina, G. P. Smirnova, and E. G. Chesnokova, in: Current Problems in Genetics of Behavior [in Russian], Nauka, Leningrad (1975), p. 195.
4. M. S. Ritsner, Pediatriya, No. 8, 76 (1974).
5. V. K. Rudzit, Tryptophan [in Russian], Meditsina, Leningrad (1973).